ATIS 0900004

This technical report describes the methods used to distribute frequency and time within an office. It describes the current Timing Signal Generator (TSG) based architecture and the changes needed to allow this frequency distribution system to deliver time also. Both time and frequency can be delivered by physical layer methods and packet layer methods. For physical layer methods, the document includes synchronous Ethernet, 1 PPS with time code, and DTI. For packet layer methods, both PTP and NTP are discussed. Also, the use of physical layer frequency synchronization with packet-layer time synchronization (specifically synchronous Ethernet with PTP) is described. Since this is a technical report, the interfaces, protocols, and requirements are not defined in this document. Technical details can be found in normative references from ITU, IEEE, or ATIS.